Treatment of cystic disease with TNF-α

ABSTRACT

A method for treating polycystic kidney disease in an individual in need thereof. This method includes identifying a mammal having a cystic disease and administering to the mammal a pharmacologically effective anti-cystic amount of TNF-α or an agent which stimulates TNF-α production in vivo. The agent is administered in a pharmacologically acceptable carrier, excipient or diluent.

STATEMENT OF GOVERNMENT SUPPORT

This invention was made with United States government funding under NIHGrant No. DK 40700. The government may have certain rights in theinvention.

FIELD OF THE INVENTION

The present invention relates to treatment of cystic diseases. Morespecifically, the invention relates to treatment of polycystic kidneydisease by administration of TNF-α or agents which stimulate productionof TNF-α.

BACKGROUND OF THE INVENTION

There are many human diseases which result in the formation of cystswhich contain either semi-solid or fluid material. The contents of acyst sometimes drive from normally retained fluid (e.g. a sebaceous cystcan contain fluid from a blocked sebaceous gland) or from a parasiticinfection. Benign cysts can occur in the ovary, spleen, lungs, kidneyand liver, where they are often congenital. Some congenital cysts resultfrom fetal malformations and developmental failure while others aredirects results of a disease state.

The polycystic kidney diseases (PKD) are a group of disorderscharacterized by the presence of a large number of fluid-filled cyststhroughout grossly enlarged kidneys (Gabow et al., Diseases of theKidney, Schrier et al. eds., 1992). In humans, PKDs can be inherited inautosomal dominant (ADPKD) or autosomal recessive (ARPKD) forms. ADPKDis the most common, dominantly-inherited kidney disease in humans,occurring at a frequency of about 1 in 800. ARPKD occurs at a frequencyof about 1 in 10,000. Clinically, PKD represents a major cause ofend-stage renal disease. Microdissection, histochemical and immunologicstudies show that cysts in ARPKD kidneys arise from focal dilations ofmedullary collecting ducts (McDonald, Semin. Nephrol., 11:632-642,1991). Mutations in at least three different loci have been associatedwith ADPKD in humans, including PKD1 on chromosome 16, PKD2 onchromosome 4, and the not yet mapped PKD3 (Reeders et al., Nature,317:542-544, 1985; Kimberling et al., Genomics, 18:467-472, 1993; Daoustet al., Genomics, 25:733-736, 1995). The ARPKD mutation is on humanchromosome 6 (Zerres et al., Nature Genet., 7:429-432, 1994). Themolecular mechanisms leading to cyst enlargement and progressive loss ofrenal function in PKDs are not completely understood. Besides dialysisand transplantation, which are palliative, there are no preventive orcurative treatment for PKDs.

In 1977, it was reported that a recessive congenital polycystic kidney(cpk) disease arose spontaneously in C57BL/6J mice (Preminger et al., J.Urol., 127:556-560, 1982). The cpk mutation has been mapped to mousechromosome 12 (Davisson et al., Genomics, 9:778-781, 1991). Kidneymaldevelopment and progression of PKD in C57BL/6-cpk/cpk mice have beencharacterized in detail (Preminger, ibid.; Mandell et al., Am. J.Pathol., 113:112-114, 1983). Affected animals appear normal at birth andhave microscopic dilations of their proximal renal tubules. Theseenlarged tubules develop into cysts. At 10-13 days of age, homozygouscpk/cpk animals may be recognized by protuberant abdomens resulting fromgreatly enlarged kidneys. After day 10-12, additional cysts developrapidly from dilations of medullary collecting ducts. Consequently, thekidneys rapidly enlarge, reaching almost 2.0 g in kidney weight at day24 compared to about 0.18 g for age-matched normal kidneys. Cysticexpansion is accompanied by the apoptotic loss of non-cystic nephrons(Woo, New Engl. J. Med., 333:18-25, 1995). Concomitant with kidneyenlargement, there is a gradual decrease in kidney function with bloodurea nitrogen (BUN) reaching 120 mg/dL by 24 days of age. Polycysticmice become progressively lethargic and die by 28-35 days of age due torenal failure.

Hallmark features of cystic changes in human PKD epithelia such ascellular hyperplasia and abnormal basement membrane are observed in cpkcysts at both the light and electron microscopic level (Gattone et al.,Am. J. Kidney Dis., 17:606-607, 1991). The accumulation of fluid incysts indicates abnormal fluid transport in cpk cystic epithelia. Thepresence of altered expression of basement membrane (Taub et al., KidneyInt., 37:1090-1097, 1990; Ebihara et al., Lab. Invest., 58:262-269,1988), altered growth-controlling gene expression (Horikoshi et al.,Kidney Int., 39:57-62, 1991; Gattone et al., Dev. Biol., 138:225-230,1990; Cowley et al., J. Am. Soc. Nephrol., 1:1048-1053, 1991), alteredtargeting of the normally basolaterally sodium-potassium ATPase and EGFreceptor (Avner et al., Proc. natl. Acad. Sci. U.S.A., 89:7447-7451,1992; Orellana et al., Kidney Int., 47:490-499, 1995), and expression ofdevelopmentally dedifferentiated phenotypes (Harding et al., Dev. Biol.,146:483-490, 1991) make the cpk mouse a useful animal for studying thediverse renal pathobiologies of PKD. The overall progression of PKD isvery similar in the cpk mouse and in humans.

The microtubule-specific drug taxol significantly inhibits theprogression of PKD and significantly prolongs the survival of polycysticcpk mice (Woo et al., Nature, 368:750-753,1994; PCT W094/08041). Insteadof dying of azotemia by four to five weeks of age, polycystic micetreated weekly with taxol can survive to more than six months of age.Taxol binds to microtubules and inhibits microtubule depolymerization.Accordingly, the microtubule cytoskeleton has been postulated to play arole in pathogenesis of PKD in the cpk mouse. In addition to itsmicrotubule stabilizing effects, taxol specifically induces theexpression of tumor necrosis factor-α (TNF-α) in macrophages andlymphocytes. The ability of taxol to induce production of TNF-α is notshared by other members of the taxane family.

TNF-α is a pleiotropic cytokine that mediates diverse cellular responsesincluding cytotoxicity, cytostasis, proliferation, differentiation andthe expression of specific genes (Beutler et al., Science, 264:667-668,1994). TNF-α is cytotoxic for a wide variety of tumor cells, but onlytoxic to a few selected normal cell types (Carswell et al., Proc. Natl.Acad. Sci. U.S.A., 72:3666-3670, 1975; Tsujimoto et al., Proc. Natl.Acad. Sci. U.S.A., 82:7626-7630, 1985). Despite the presence of cellsurface TNF-α receptors, the majority of normal mammalian cells areresistant to the cytotoxic effects of TNF-α (Tsujimoto et al., ibid). Inaddition, TNF-α is protective against apoptotic cell death in severalcell types (Wong et al., Science, 242:941-944, 1988; Mangan et al., J.Immunol., 146:1541-1546, 1991; Warner et al., Am. J. Physiol.,260:L296-L301, 1991).

Thus, there is a need for a therapeutic agent capable of treating cysticdisease. The present invention satisfies this need.

SUMMARY OF THE INVENTION

One embodiment of the present invention is a method of treating a mammalhaving a cystic disease, comprising the step of administering to themammal a pharmacologically effective anti-cystic amount of TNF-α or anagent which stimulates TNF-α production in vivo, with the proviso thatthe agent is not taxol, the agent being administered in apharmacologically acceptable carrier, excipient or diluent. Preferably,the mammal is a human. According to one aspect of this preferredembodiment, the cystic disease is breast cysts, bronchogenic cysts,choledochal cysts, colloidal cysts, congenital cysts, dental cysts,epidermoid inclusions, hepatic cysts, hydatid cysts, lung cysts,mediastinal cysts, ovarian cysts, periapical cysts, pericardial cysts orpolycystic kidney disease. Advantageously, the cystic disease comprisesa polycystic kidney disease. Preferably, the administering step isintravenous, intraperitoneal or intramuscular.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the survival of taxol-treated polycystic cpk mice. Thenumber of days after taxol or placebo treatment is shown on the x-axisand the survival rate is shown on the y-axis.

FIG. 2 shows the survival of TNF-α treated cpk mice. The number of daysafter TNF-α or placebo treatment is shown on the x-axis and thecumulative survival is shown on the y-axis.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a method of treating PKD byadministration of TNF-α or an agent which stimulates the production ofTNF-α. Although the treatment of PKD is exemplified herein, thetreatment of any cystic disease is within the scope of the invention.Such cystic diseases include breast cysts, bronchogenic cysts,choledochal cysts, colloidal cysts, congenital cysts, dental cysts,epidermoid inclusions, hepatic cysts, hydatid cysts, lung cysts,mediastinal cysts, ovarian cysts, periapical cysts, pericardial cysts orpolycystic kidney disease.

TNF-α or an agent which stimulates TNF-α production may be administeredby various routes, including intravenously, intraperitoneally,intramuscularly, intraarterially, subcutaneously, orally or in any otherappropriate way known in the art in a pharmaceutically acceptablecarrier, excipient or diluent. TNF-α for parenteral administration maybe in the form of a sterile injectable preparation, such as a sterileinjectable aqueous or oleaginous suspension. This suspension may beformulated according to methods well known in the art using suitabledispersing or wetting agents and suspending agents. The sterileinjectable preparation may also be a sterile injectable solution orsuspension in a parenterally acceptable diluent or solvent, such as asolution in 1,3-butanediol. Suitable diluents include, for example,water, Ringer's solution and isotonic sodium chloride solution. Inaddition, sterile fixed oils may be employed conventionally as a solventor suspending medium. For this purpose, any bland fixed oil may beemployed including synthetic mono- or diglycerides. In addition, fattyacids such as oleic acid may likewise be used in the preparation ofinjectable preparations.

The tolerated dose of recombinant TNF-α in phase I clinical trials is150,000 units/kg (Bollon et al., J. Cell. Biochem., 36:353-367, 1988).The preferred effective dose range of TNF-α for treatment of humancystic diseases is between about 50,000 units/kg and 150,000 units/kg; amore preferred dose is between about 75,000 units/kg and about 125,000units/kg; a most preferred dose is about 100,000 units/kg. Thistreatment is typically repeated every two or three days until asignificant improvement in the cystic disease is observed. TNF-α can beadministered either before a cyst has formed, to prevent its formation,or after a cyst has already been detected.

In addition, agents which stimulate TNF-α production are also useful intreating cystic diseases. Such agents include, for example, thenon-steroidal antiinflammatory drugs indomethacin, naproxen andibuprofen (Drugs Exp. Clin. Res., 19:243-248, 1993), tenidap (Golding etal., J. Immunol., 154:5384-5390, 1995), a synthetic low-toxicity lipid Aanalog (Akimoto et al., lnt. J. Immunopharmacol., 16:887-893, 1994) andimiquod (J. Leukoc. Biol., 55:234-240, 1994. The ability of suchcompounds to treat cystic diseases may be determined by one of ordinaryskill in the art using the mouse cpk polycystic kidney disease model asdescribed in Example 1 for TNF-α and taxol treatment.

EXAMPLE 1 TNF-α and taxol treatment of cpk mice

Heterozygous C57BL/6-cpk/+ breeder mice were obtained from the JacksonLaboratory (Bar harbor, Me. The cpk mouse colony was maintained bymating known heterozygotes. Mice were kept with their mothers until theywere weaned at 28 days of age.

Taxol obtained from the Drug Synthesis and Chemistry Branch of theNational Cancer Institute (Bethesda, Md.) was dissolved at 10 mg/ml indimethyl sulfoxide (DMSO) and stored at -20° C. Taxol treatment wasinitiated on 10 day old polycystic cpk mice diagnosed to be polycysticby the presence of palpably enlarged kidneys. Mice were injectedintraperitoneally with 10 μg of taxol per gram body weight on day 10 and100 μg taxol per animal on subsequent weeks. Polycystic mice treatedwith an equal volume of DMSO were used as controls.

Weekly taxol treatment clearly increased the survival rate of cpk mice(n=43) compared to control (carrier vehicle treated mice (FIG. 1). Whenweekly taxol treatment was initiated at 10 days of age, 60% of allpolycystic mice survived past 40 days of age, while at this time, 80% ofthe untreated polycystic cpk mice had died. 35% of polycystic micetreated weekly with taxol lived past 90 days of age, while allpolycystic cpk mice treated with DMSO died. Statistically, thedifference in survival between control and taxol treated mice is highlysignificant (Log-rank chi-square=7.80 and p=0.005). The serum creatinineof three taxol treated polycystic cpk mice when sacrificed at 90 days ofage was 2.8±0.8 mg/dL (vs. 6.0 mg/dL in untreated 24 day old mice).

Sterile recombinant murine TNF-α (1 mg/ml, Genentech, South SanFrancisco, Calif.) was stored at 4° C. in phosphate buffered saline(PBS). Beginning on day 7 after birth, the entire litter of mice fromselective matings was injected intraperitoneally with 2 μl TNF-α everyother day. After day 10, only mice with palpable polycystic kidneyscontinued to receive TNF-α. Polycystic mice identically treated with PBSwere used as controls. All polycystic mice were continually treated forthe duration of their life.

All TNF-α experiments were initiated on day 7 by administering TNF-α tothe entire litter. Despite treatment, the kidneys of polycystic cpk micetreated with TNF-α on day 7 continue to enlarge and become palpable byday 10. The kidneys of mice without palpably enlarged kidneys by day 10were all histologically normal. FIG. 2 compares the survival of 21polycystic cpk mice given 2 μg TNF-α every other day and 25 polycysticcpk mice treated similarly with saline. Over 90% of TNF-α treatedpolycystic cpk mice survived past 40 days of age. In contrast, only 20%of the saline treated cpk mice survived beyond 40 days of age. Almost50% of TNF-α treated mice survived past 100 days of age. In contrast,none of the saline-treated mice lived past 90 days of age.Statistically, the difference in survival between control and TNF-αtreated cpk mice is highly significant (Log-rank chi-square=24.17 andp<0.0001). Because taxol is known to stimulate TNF-α production, theability of taxol to inhibit the progression of PKD in polycystic cpkmice is due, at lest in part, to this activity.

For histology studies, animals were sacrificed and their kidneys werefixed overnight in 10% neutral buffered formalin (Fisher Scientific,Pittsburgh, Pa.), dehydrated in ethanol, infiltrated and embedded inparaffin. Five micron histological sections were prepared and stainedwith periodic acid-Schiff stain, counter stained with hematoxylin andvisualized by light microscopy.

A striking contrast was observed between the tightly packed functionalnephrons seen within the histological sections of normal mice and theapoptotic loss of non-cystic nephrons in the kidneys of polycystic mice.Direct comparison between normal mice and polycystic mice at 10 days ofage revealed a loss of approximately 50% of the non-cystic nephrons.Almost all of the remaining non-cystic nephrons were rapidly andcompletely lost during the next ten to fourteen days. By the third tofourth week after birth, only a few life sustaining neurons remained.during the three to four weeks of rapid progression to complete renalfailure, no signs of tubular necrosis, interstitial inflammation orinterstitial fibrosis were detected in the polycystic cpk kidneys.

Compared to kidneys obtained from a 28 day old azotemic polycystic cpkmouse, kidneys obtained from apparently healthy polycystic cpk micetreated with TNF-α for 90 days were significantly smaller in size.Kidneys from TNF-α treated polycystic cpk mice appeared to be verysimilar to kidneys from polycystic cpk mice treated weekly with taxolfor the same length of time by both gross and histological criteria.Both of these treated kidneys had far fewer and much smaller cysts thankidneys from untreated or saline treated polycystic cpk mice.Histological examination revealed the presence of a number ofhypertrophied nephrons in kidneys from both the TNF-α and taxol treatedmice. Significant interstitial fibrosis was also observed in kidneys ofboth TNF-α and taxol treated mice. Both treated groups have kidneys witha large fluid filled central lumen which results from enlargement of therenal pelvis. This feature is most likely a result of the chronic renaldisease state the treated mice experienced and not a result of the TNF-αor taxol treatment.

Renal function was assessed as described in the following example.

EXAMPLE 2 Determination of Renal Function

Mice were sacrificed at the indicated age and 0.5 ml blood was collectedfrom the aorta. Serum creatinine was measured in triplicate using acommercial creatinine kit (Sigma, St. Louis, Mo.) with the followingmodifications. Because hemolysis of serum strongly interfered with thecreatinine assay, hemoglobin in serum samples (100 μl) was precipitatedwith trichloroacetic acid at a final concentration of 10%. Precipitatedproteins were removed by centrifugation at 13,000 rpm for 10 minutes andthe serum neutralized to pH 7.0. Creatinine determination was preformedwith 25 μl of the neutralized serum in flat-bottom rigid microtiterplates (Corning, Corning, N.Y.) according to the creatinine assay kitinstructions, but scaled down to a 250 μl assay volume. Absorbance bothbefore and after addition of the acid reagent was recorded at 490 nmusing a Molecular Device VMax 96 well plate reader.

The average serum creatinine of three active polycystic mice treatedwith TNF-α was 3.3±0.6 mg/dl when they were sacrificed at 90 days ofage.

Human cysts may be treated in vivo as described in the followingexample.

EXAMPLE 3 Treatment of Human Cysts

A subject having a cystic disease or at risk for developing a cysticdisease is first identified. For example, a subject can be identified bya physician, who diagnoses that subject as having ADPKD. Afteridentifying an appropriate subject for treatment, that subject isintravenously administered a pharmaceutically effective dose (e.g.100,000 units/kg of recombinant human TNF-α. TNF-α can be administeredeither before a cyst has formed, in order to prevent its formation, orafter a cyst has already been detected in a subject. This administrationis repeated, for example, every three days during the time the patienthas or is susceptible to developing a cyst. In this way an effectiveamount of the compound can be maintained in the subject.

It should be noted that the present invention is not limited to onlythose embodiments described in the Detailed Description. Any embodimentwhich retains the spirit of the present invention should be consideredto be within its scope. However, the invention is only limited by thescope of the following claims.

What is claimed is:
 1. A method for treating a mammal having a cysticdisease, comprising the step of administering to said mammal apharmacologically effective anti-cystic amount of TNF-α in apharmacologically acceptable carrier, excipient or diluent.
 2. Themethod of claim 1, wherein said mammal is a human.
 3. The method ofclaim 1, wherein said cystic disease is selected from the groupconsisting of breast cysts, bronchogenic cysts, choledochal cysts,colloidal cysts, congenital cysts, dental cysts, epidermoid inclusions,hepatic cysts, hydatid cysts, lung cysts, mediastinal cysts, ovariancysts, periapical cysts, pericardial cysts and polycystic kidneydisease.
 4. The method of claim 3, wherein said cystic disease comprisesa polycystic kidney disease.
 5. The method of claim 1, wherein saidadministering step is selected from the group consisting of intravenous,intraperitoneal, intraarterial, subcutaneous, oral and intramuscularadministration.
 6. The method of claim 5, wherein said administeringstep is intravenous.